Engine starter control



1940. M. H. ELKIN 2,202,550

ENGINE STARTER CQNTROL Filed June 29, 1938 2 Sheets-Sheet 1 h]: n1 1 gig I INVENTOR. JAWS/s M filial/ 0 A TTORNEY.

May 28, 194-0. M.'H. ELKIN ENGINE STARTER CONTROL 2 Sheets-Sheet 2 Filed June 29. 1938 INVENTOR. manual it. 66100:,

ATTORNEY.

UNITED 's 'rss PATENT. OFFICE moms s'raa'raa common I Manuel 1!. Elkin, Elmira Heights, N. Y., assignor,

by mean. assignments, to Bendix Aviation Corporation, South Bend, 11:11., a corporation of Delaware Application June 29, 1938; Serial No. 216,554

'4 Claims. (Cl. 290-47) 'nie present invention relates to automatic encontrol device s including an electromagnetic gine starter controls and more particularly to a starting switch 4 which is connected by a lead 5 device for automatically opening the circuit of to a starting motor SM grounded at 6 to complete an electrical starter if the engine fails to start the starting circuit.

5 for any reason after a predetermined time of A control circuit for the magnetic starting 5 cranking. switch 4 is provided which includes battery i, a

Various types of so-called cranking time limthermostatic cranking time limiter device indiiters have heretofore been proposed and used to cated generally by numeral 1, a backfire proteca considerable extent, most of which hav detive device 8 and the relay 9 of the starter conw pended on some form oi thermostatic device trol device S. Relay 9 includes contacts ii and 10 which gradually heats up during cranking and H which are maintained open during self-opbreaks the starting circuit when a predetermined eration of the engine either by an engine-driven tem erature i xc d d, Devi or thi h rgenerator G or by an intake vacuum operated I acter as heretofore constructed have had the device ii. In greater detail, this control circuit 5 disadvantage that they are affected by the comprises a lead It connected tothe battery lead 1 ambient temperature and are therefore not uni- 3 y a nu l n n swit h "I, and to the form in action. Moreover, inc th battery cranking time limiter l, a lead i5 connecting the which supplim power for heating the thermostat nk n im limiter t0 the backfire circuit is usually the source of power for cranking the breaker 8,'a lead l6 connecting the circuit breaker engine, a low battery and a eo1d engin may to the coil I! of the starting switch, and a lead Iii redu e th available voltage to a point wher th i8 connecting said coil to contact ll, contact i2 thermostat will not heat up sufficiently to funcbeing grounded as in i ate at t. tion, and abortive cranking may continue until The cranking time limiter 1 comprise a 0011- the battery is completely discharged. tact 2| mounted on a spring arm .22 to which It is an object of the present invention to t e p r upp y l ad t is connected as indias provide a novel cranking time limit r j r t cate'd at 23. A fixed contact 24 to which the lead matic starter controls which is efflcient and re- 15 Connected is arranged to cooperate t liable in action while being simple and economthe Contact Contacts 2| n 2 re n lly ical in construction. held in engagement by an actuating member in so It is another object to provide such a device the form of a spri -Dr e plunger 25 which is which is substantially unaffected in its action slidably mounte in the 85 8 25 0 e cranking by the prevailing ambient temperature. time limiter and is held in normal position It is another object to provide such a device a a nst the ction o a spr 21 y means of a which is substantially uniform in action irrespeclatch 28 engaging a shoulder 29 on the plunger. tive of variations in the state of charge of the According to the present invention, the latch cranking battery or the comparative stiffness 28 is composed of two strips of thermostatic maof the engine to be cranked. terial 8| and 32, thestrip 3! being rigidly mount- Further objects and advantages will be ape on the cas 26 in any su table way as inparent from the following description taken in dicated at 33, and the strip 32 being attached at connection with the accompanying drawings in one end to the free end of the strip 3| as indicated 40 which: a at 34. A sheet of insulating material 30 such Fig. 1 is a semi-diagrammatic illustration of an as mica is interp d w n e at ached ends electrical system for an internal combustion en- 01' the thermostatic strips in order to oppose the gine including automatic starter controlling transfer of heat by conduction from strip 32 to means embodying a preferred form of the present strip 3i. 5 invention; The thermostatic strip 3| is arranged with its Fig. 2 is an enlarged detail in elevation and i h c fl i t sid away from h p un r 5 partly in section of the cranking time limiter deso that a rise in temperature of this strip tends vice; and to make it bend toward the plunger. The ther- Fig. 3 is a section taken substantially on the mostatic strip 32, however, is oppositely arranged 50' line 3-3 of Fig. 2. v so that a rise in temperature thereof tends to In Fig. l of the drawings an electrical system make it bend away 1mm the pl er 2 in a is illustrated comprising a starting circuit includdirection to unlatch the plun y this ns. ing a battery I grounded at 2 and connected the latch 28 of such composite structure is subby a lead 3 to a commercial form of starter stantially unaffected by changes inambient tem- 5| perature since the reactions oi the parts it and 32 to changes in ambient temperature substantially cancel each other.

Means are provided for applying heat to the thermostatic element 32 only of the latch 28 during the cranking operation including a heater coil 35 grounded at one end by noeam or a flexible lead it, the other end being connected to a lead 3i attached to the starting motor lead 6 so as to be energized from the battery [1 during the cran ing operation. in order that the heating effect ill) ot the coil may be substantially uniform ir respective of variations in the condition of. charge of the battery I] and the stiffness of the engine to be cranked, 'rneans are provided for maintaining a substantially constant how of current through the heater coll. under all conditions. As here shown, this means is in the iorrn of a ballast tube 38 connected by a lead 89 to the heater coil and by a lead ll to the supply lead 37/.

The spring arm 22 carrying contact 20 is provided with a terminal loop l2 bearing on. the surface of plunger 25 so as to maintain. contacts 2t, 26 closed while the plunger is retained in its normal position, as illustrated, by the latch 28. Plunger is provided with groove 33 which i moved by the spring El into registry with the loop if? or" spring arm when the plunger is released by the latch, so as to permit contacts 2t, 23 to open.

The contact actuating plunger also be arranged to operate a signal or alarm oi preferred and for this purpose a spring arrn id is provided which is connected by a lead 35 to the supply lead id and carries contact 06 adapted to cooperate with a lined contact Cs? connected by a lead 68 to one or more alarm devices such as a lamp G9 or a burner 59. Elie spring arm dd is provided with a loop normally rest-= ing in a groove in plunger 25 so as to permit contacts it ll to be open. Release or the plunger 25 by latch 28 causes the cylindrical portion of the plunger to engage the loop 62 of STQFE'KEQ' i l and close contacts G6, ll].

The backfire circuit brealzer 8 comprises a pair or contacts 5 3 and 55, contact 5 3 being mounted on a spring arm connected to lead it and contact being connected to lead l6. A. plunger 5? is arranged to be actuated by lntal-re pressure of the engine to be cranked in any suitable way, not illustrated, so as to engage the spring arm 56 and open contacts 55, 55. In order to secure a time delay prior to reclosure of these contacts, spring arm is preferably made of thermostatic material and the plunger ill is permitted to ground the circuit whereby a heavy flow of current through the thermostatic arm 56 heats it and causes it to expand away from contact The relay 9 of starter control S comprises a coil to energized from the starting circuit for opening the relay contacts when the engine starts, in the manner set lorth in the patent to Loehr and Burdick No. l,9l2,9tl-i. in order to hold open contacts M, ii! during self-operation of the engine, relay 9 is provided with a coil 58 connected by a lead to the engine-driven generator G. For isolated installations, the genera tor lockout is preferably supplemented by an intake vacuum lockout, here shown in the form of the vacuum switch it operated from engine intake vacuum by means of any suitable connections, not illustrated, and connected by the lead iii to the generator coil lead it'll, and by a lead to the power supply lead i l of the control circuit. since the coil 58 of relay t is designed to operate on quite low voltage in order to perform its lockout function at low speeds of the generator. energization thereof by full battery voltage is unnecessary and might cause premature opening of contacts it, 02 it the vacuum switch it is closed during cranking.' lit is preferred, there-= fore, to insert a resistance in the lead 62 to cut down the battery voltage to a suitable value. As here illustrated, this resistor is conveniently arranged in the casing 26 of the cranking time limiter as indicated at 68.

in the operation oi the device, closure of the ignition switch fill completes the control circuit from battery i through lead 00 to the cranking time limiter, through contacts 20, 2G thereoi and lead 05 to the backfire circuit breaker 8, through contacts 6 thereof and lead ill to the coil ll of the magnetic starting switch 0, and through lead it and contacts ll, 02 to the ground at it). Consequent closure oi the starting switch l coin pletes the starting circuit through leads 8 and 5 to the starting motor which is thereupon energlzed to cranls the engine. Upon closure of starting circuit, current news through leads Si,

Si, ballast tube 38 and lead 39 to the heater coil 35 of the thermostatic latch 28, causing it to gradually heat up. it the engine becomes'seli operative before the latch heats up sutilciently to release the plunger the relay 9 opens con" tacts it, 02, breaking the control circuit and opening the starting switch 6. contacts it, it are held open by the coil 58 o the relay 9 long as generator effective or there is suhicient vacuinn in the engine intahe to actuate the vacuum lockout device it).

ll, however, for some reason the engine should not start within a suitable predetermined time limit, the thermostatic element 32 of latch becomes heated suhlciently to release the plunger 2L3. Contacts 20, 2d are thereupon opened, brealo the control circuit and causing the starting switch (I to open, and contacts 60, it are closed to operate the signal devices 39, 5t. lithen the starting switch l opens, the circuit for the heatlng coil 35 is also brolren so that the coil cools off. it is merely necessary, therefore, for the attendant when summoned by the signal device to press the plunger 26 boot: to its normal posh time after correcting the condition oi the engine which prevented it ironrstarting, whereupon starting opera ion will be resumed.

Although but one ionn oi the invention has been shown and described in detail, it will be understood that other embodiments are possible and various changes be made in design and arrangement or the parts without departing from the spirit or the invention as deiined in the claims appended hereto.

What is clairncd is:

1. In an engine starter control, a starting circuit including a magnetic starting switch, a control circuit therefor including a pair of contacts rneans for holding the contacts normally closed including a slidable plunger, a latch holding the plunger in contact-closing position comprising two oppositely arranged thermostatic blades connected end to end, and a heating coil for one of said blades energized from the starting circuit to cause the latch to release the plunger and permit the contacts to open after a predetermined time of cranking.

2. In an engine starter, a starting circuit including a battery, a starting motor and a magnctlc starting switch, a control circuit for the starting switch including a cranking time limiter having thermostatically opened contacts, and

contacts opened when the engine starts, an engine-driven generator, means energized thereby for holding open said last-mentioned contacts during self-operation of the engine, and means responsive to intake vacuum of the engine for energizing said holding means from the battery.

3. In an engine starter, a starting circuit in cluding a battery, a starting motor and a magnetic starting switch, a control circuit for the starting switch including two sets of contacts in series, thermostatic means for opening one set of contacts after a predetermined time of closure of the starting switch, means for opening the second set of contacts responsive to self-operation of the engine, a generator driven by the engine to be started, a solenoid energized thereby to hold open the second set of contacts, a circuit from the battery through said solenoid including a resistor and a pair of normally open contacts, and means responsive to intake vacuum of the engine for closing said last-mentioned contacts. 4. An engine starter control as set forth in claim 1 characterized in that connecting means for energizing the heating coil for-the thermostat are provided which include means for maintaining a substantially constant flow of current therethrough irrespective of variations in voltage.

MANUEL H. ELKIN. 

